Phasing a scheme without triggering a higher threshold

Splitting a scheme into phases to stay under a threshold works for programme and cash flow and almost never works as a way of avoiding an obligation. Phased application thresholds are assessed on the development as a whole where the phases are functionally connected, so a 14-unit site submitted as two applications of seven is usually still a major application, still crosses the affordable housing threshold, and still gets screened for environmental impact as one project.

That does not make phasing pointless. It means the reason for phasing has to be real, and the description of development has to be written so that each phase stands up on its own terms.

Why phasing looks attractive and often fails

The thresholds are close together and the step changes are expensive. Ten dwellings turns a minor application into a major one, with a 13-week determination period, a higher fee, statutory publicity and, in most authorities, an affordable housing requirement. Fifty units brings a Statement of Community Involvement and a Transport Assessment into scope in many local validation lists.

So the temptation is obvious. Submit nine now, nine more next year.

Authorities see this pattern constantly and the response is procedural rather than adversarial. The case officer looks at the red line, the ownership, the access arrangement and the timing, and asks whether the second application is a separate project or the second half of one. If it is the second half, the assessment follows the whole.

How authorities assess cumulative effect

There is no statutory bar on selling or developing land in parcels. What the system does instead is treat the effects cumulatively.

Three questions decide it in practice. Do the parcels share an access, a drainage strategy or an open space provision that only works if both are built? Is the land in the same ownership or subject to an option held by the same party? Was the second parcel identified in the first application's supporting documents, for example on an illustrative masterplan or in a phasing note?

Answer yes to two of those and the authority will assess the parcels together. The consequence is not usually refusal. It is that the affordable housing, the play space, the education contribution and the transport work are calculated on the total.

An honest phasing plan submitted up front tends to get a better reception than a second application that arrives six months later with a straight face.

EIA and the treatment of related development

Screening under the Town and Country Planning (Environmental Impact Assessment) Regulations 2017 is where splitting carries the sharpest risk. Schedule 2, paragraph 10(b) covers urban development projects, with screening thresholds including development of more than 150 dwellings and an overall development area of more than 5 hectares.

Schedule 3 of the same Regulations requires the screening authority to consider the cumulation of the proposal with other existing or approved development. The courts have held that where two proposals are functionally interdependent, they must be screened as a single project rather than separately.

A negative screening opinion obtained on a deliberately narrow description is fragile. If the second phase comes forward and the true scale becomes clear, the earlier opinion can be revisited, and a permission granted without a required environmental statement is vulnerable to challenge. An Environmental Impact Assessment environmental statement must be prepared by competent experts under the 2017 Regulations, so a draft is a starting point for that team rather than a substitute for it.

Request a screening opinion on the whole landholding if you intend to bring forward more than one parcel. A negative opinion on the full extent is worth more than two narrow ones.

Infrastructure obligations across phases

Section 106 obligations and the Community Infrastructure Levy behave differently across phases, and this is where phasing does real work.

CIL is charged on chargeable development when it starts. A permission that is expressly phased is treated as a series of separate chargeable developments, so the levy falls due phase by phase rather than in one payment on the first spade in the ground. Outline permissions are phased by definition where phases are set out. Full permissions need the phasing to be written into the permission itself, which means drawing it into the description and the approved plans rather than bolting it on later.

Section 106 obligations can be drafted with phase triggers in the same way: affordable housing delivered pro rata per phase, contributions paid on occupation of a stated number of units within each phase, highway works tied to the phase they serve.

Get the phase boundaries onto a plan and referenced in the description of development. Retrofitting phasing onto an unphased full permission normally needs a section 73 application.

Where phasing is legitimate and accepted

Phasing is accepted, and often welcomed, where it reflects something real about the site or the delivery.

Ground conditions or remediation that only allow part of the site to be worked at once. A land assembly where one parcel has an unresolved title issue. A drainage outfall that cannot be built until an adjoining scheme completes. Flood risk sequencing that puts the lower-risk parcel first. A self-build or custom-build element delivered on a different timescale. An employment parcel whose occupier is not yet identified.

In each case the phasing has a cause outside the threshold. Say so, in the Planning Statement, in one paragraph, with the evidence behind it.

Evidence that a phase stands alone

Where you want a parcel treated as its own project, the file has to show independence rather than assert it.

1. A red line that includes its own access from the public highway, not a spur off the other parcel's estate road.
2. A drainage strategy with its own outfall and attenuation, not shared storage.
3. Open space, parking and refuse provision sized for that parcel alone and deliverable on it.
4. Different ownership, or a genuine arms-length disposal with dates.
5. No reference to the adjoining land in the masterplan, the illustrative layout or the supporting statements.
6. A Transport Assessment or statement whose trip generation is calculated for that parcel, while still assessing committed development on the adjoining land as part of the baseline.

Point five catches people out. An illustrative masterplan showing the wider site is helpful for placemaking and fatal to an argument that the parcels are unrelated.

Drafting the description of development

The description is the boundary of the permission and it is where phasing is won or lost. Write it to say what is being permitted, in how many phases, and what is reserved.

"Erection of 24 dwellings in two phases (Phase 1: 12 dwellings; Phase 2: 12 dwellings) with associated access, parking and landscaping, in accordance with the phasing plan" tells the authority, the CIL officer and the section 106 solicitor the same thing. A description that says only "erection of 24 dwellings" does not.

Where the total crosses the affordable housing threshold, an Affordable Housing Statement that sets out delivery per phase is better received than one that argues the threshold is not engaged. Our note on planning fees and thresholds on a growing scheme covers the fee consequences, and splitting a site below a planning threshold deals with the separate question of selling parcels to different parties.

This is general guidance, not legal advice, so check the position with your local planning authority or a qualified professional before relying on it.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.